Thank you Ron! That is exactly what I wish to see: the "real math" behind the
equations and not just how to use them.

How can I get a hold of that "functions book for Excel 4"? I presume there
no longer are such functions books for newer Excel versions? Once again, many
thanks.


"Ron Coderre" wrote:

Have we gotten so far away from "real math" that we forget that Excel's
functions are not math, but are actually doing the math for us?

The Excel help documentation explains how to use the PMT function, not the
mathematics behind that function. Back when Excel 4 came out...in a
box....with 10 disks....and with books...there was a functions book that
included all of the math used to derive each function's results.

In the case of the PMT function, that documentation went something like this:
---------------------

P = (Pv*R) / [1 - (1 + R)^(-n)]

where

Pv = Present Value (beginning value or amount of loan)
APR = Annual Percentage Rate (one year time period)
R = Periodic Interest Rate = APR/ # of interest periods per year
P = Monthly Payment
n = # of interest periods for overall time period (i.e., interest
periods per year * number of years)
---------------------

I believe that's what the OP was hoping to find.

I haven't seen that kind of function documentation for Excel in quite some
time.
***********
Regards,
Ron

XL2002, WinXP


"Fred Smith" wrote:

Yes, they do. As you've been told, it's in Help. It's actually pretty
straightforward. What is it about the formula in Help that you don't understand?

--
Regards,
Fred


"ai18ma" wrote in message
...
Many Thanks for the suggestions as well as the offer to help with the
specific equation. Nonetheless, it is not just pmt, I would very much like to
have a better undertanding of the whole issue. Does Microsoft publish such
information somewhere?

"ai18ma" wrote:

Good Day,

How do I get to see the equation behind Excel Functions? For instance, the
result of pmt() is not making sense to me, I'd like to see what this function
is doing and how it is calculating its value. Trial and Error is rather
time-consuming and tedious. What is the better way of doing this? Thnx for
the help.